Week 9 Flashcards
(46 cards)
What is somatosensation?
Sensory information from the body including proprioception (sense of ones self), exteroception (info from skin e.g. touch, pain), interoception (sense of organs)
What are chemorecptors?
Detect info for chemicalse.g. blood ph
What are mechanoreceptors?
Sensitive to physical dystortion such as touch, pressure, stretch or vibration
What are nociceptors?
Sensetive to pain
What are thermo receptors?
Sensative to change in temp
What are muscle spindles?
The sensory receptors within the skeletal muscle belly
- Detect stretch
What are golgi tendon organs (GTO)?
Found in tendons near the musculotendinous junction
- Detect force/muscle tension
What are joint receptors?
Respond to mechanical deformation of joint capsules and ligaments
- Helps determine whether the joint is positioned right or wrong
What are rods and cones?
Special sensory receptors for vision
What are hair cells within the vestibular cochlea nerve?
Special sensory receptors for hearing and balance
What are chemoreceptors used for?
Special sensory receptors for taste and olfaction
What are receptive fields?
The area from which a neuron will pick up sensory information – if you touch outside the receptive field that neuron will not get activated.
Large field = low sensitivity
Small field = high sensitivity
What are primary sensory neurons?
Neurons in a sensory pathway, receiving input from sensory receptors in the periphery and transmitting that information to the central nervous system
What type of neuron is the doral root ganglian and why?
Bi-polar neuron - sends 1 axon to skin and other to spinal cord to be taken to the brain
Where the the primary somatosenry cortex and what is its role?
Primary sensory cortex is located in the postcentral gyrus (right behind the central sulcus in the parietal lobe
Responsible for processing sensory information from the body, primarily touch, temperature, and pain
Where is the Secondary somatosensory cortex located and what is it’s role?
- Lower parietal lobe
- Assistant to primary sensory cortex – secondary stores and retains information
Where is the Somatosensory association cortex located and what is its role?
Directly posterior to the sensory cortex in the superior parietal lobes
- Allows you to attach meaning to touch
-Receives synthesized connections from the primary and secondary sensory cortices
Why do we have a larger represenation of the hand rather then the back in the somatosensory cortex?
More receptive fields in the finger, larger receptive fields in the back
Do nerve fibres with large diameters smaller diameter transmit signals faster?
Large diameter
What is a sensory tract?
The bundle of axons with the same origin and a common termination
What are the 3 ascending tracts bringing somatic sensory information to the brain?
- Conscious relay (aware of e.g. touch)
- Divergent relay (pain)
- Non-conscious relay (making unconscious adjustments e.g. adjusting posture)
How many neurons do the conscious relay sensory pathways have and what neuron decussates?
3 neurons
- 1st order
- 2nd order
- 3rd order
- 2nd order neurons always decussates
Where is the first order neuron located in the DCML?
In the dorsal root ganglian
Where is the second order neuron located in the DCML?
In the medulla in the brain stem
